File uploads time out after random times

I'm using ShareX to upload files via a POST request to my website (the file is POSTed to the PHP script). When uploading large files (100+ MB) and sometimes smaller ones (2-3MB) the upload will time out with "Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host." I believe this means LiteSpeed is terminating the connection but I am unsure as how to fix it.